title: The long non-coding RNA HOTAIR indicates a poor prognosis and promotes metastasis in non-small cell lung cancer.
abstract: BACKGROUND
  The identification of cancer-associated long non-coding RNAs and the investigation of their molecular and biological functions are important for understanding the molecular biology and progression of cancer. HOTAIR (HOX transcript antisense intergenic RNA) has been implicated in several cancers; however, its role in non-small cell lung cancer (NSCLC) is unknown. The aim of the present study was to examine the expression pattern of HOTAIR in NSCLC and to evaluate its biological role and clinical significance in tumor progression.
  
  
  METHODS
  Expression of HOTAIR was analyzed in 42 NSCLC tissues and four NSCLC cell lines by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Over-expression and RNA interference (RNAi) approaches were used to investigate the biological functions of HOTAIR. The effect of HOTAIR on proliferation was evaluated by MTT and colony formation assays, and cell migration and invasion were evaluated by transwell assays. Tail vein injection of cells was used to study metastasis in nude mice. Protein levels of HOTAIR targets were determined by western blot analysis. Differences between groups were tested for significance using Student's t-test (two-tailed).
  
  
  RESULTS
  HOTAIR was highly expressed both in NSCLC samples and cell lines compared with corresponding normal counterparts. HOTAIR upregulation was correlated with NSCLC advanced pathological stage and lymph-node metastasis. Moreover, patients with high levels of HOTAIR expression had a relatively poor prognosis. Inhibition of HOTAIR by RNAi decreased the migration and invasion of NSCLC cells in vitro and impeded cell metastasis in vivo. HOXA5 levels were affected by HOTAIR knockdown or over-expression in vitro.
  
  
  CONCLUSIONS
  Our findings indicate that HOTAIR is significantly up-regulated in NSCLC tissues, and regulates NSCLC cell invasion and metastasis, partially via the down-regulation of HOXA5. Thus, HOTAIR may represent a new marker of poor prognosis and is a potential therapeutic target for NSCLC intervention.
authors.affiliation: Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, Jiangsu 210029, People's Republic of China. zhaoxiawang88@hotmail.com.
authors.forename: Xiang-hua
authors.initials: XH
authors.lastname: Liu
authors.forename: Zhi-li
authors.initials: ZL
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Zhao-xia
authors.initials: ZX
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: De
mesh_terms: D017209:Apoptosis / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D062085:RNA, Long Noncoding / Q000235:genetics*
chemical_list: C561566:HOTAIR long untranslated RNA, human; C489213:HOXA5 protein, human; D018398:Homeodomain Proteins; D062085:RNA, Long Noncoding; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9